1. Field of the Invention
The present invention relates to a portable terminal, and more particularly to a method and an apparatus for communication in a portable terminal using multiple Subscriber Identity Module (SIM) cards.
2. Description of the Related Art
A dual standby and dual mode portable terminal uses multiple (e.g. two) SIM cards so that a user can select a desired SIM card for communication according to the user's need.
In order to perform communication, a portable terminal must go through a process of registering itself in a network of a mobile communication network using information recorded in a SIM card. After registering in a Public Land Mobile Network (PLMN), a particular cell in the network supported by the SIM card is selected. After camping on the particular cell in the network, the portable terminal identifies paging information and then determines whether the SIM card corresponds to a paging interval of the network on which the portable terminal has camped. When the SIM card corresponds to the paging interval of the network, the portable terminal converts to a paging standby mode. Herein, the term “paging standby” refers to identifying whether uplink/downlink data related to a communication network in a cell is generated. For example, the paging standby is served to identify whether a call request, etc. occurs.
A portable terminal using multiple SIM cards also camps on a cell corresponding to each SIM card and then performs the paging standby, so that the portable terminal can perform communication. However, the portable terminal using the multiple SIM cards may simultaneously camp on the same cell through the multiple SIM cards which may cause paging collision. When the paging collision occurs, the portable terminal can use only a network of the mobile communication network corresponding to one SIM card (e.g. a SIM card through which the portable terminal has first camped on a cell) out of the multiple SIM cards. As a result, the function of a dual standby and dual mode portable terminal which can simultaneously use the multiple SIM cards is not operative.
Hence, there is a need for proposing a solution which can solve the paging collision when paging collision occurs in the portable terminal using the multiple SIM cards.